A nearly decade-long effort to require Massachusetts employers to offer paid sick days is gaining momentum as lawmakers pass similar proposals across the country.

At least five cities and one state, Connecticut, have mandated that employers provide the benefit in recent years, with New York City poised to join them after the City Council agreed to enact legislation requiring businesses with 20 or more employees to offer five paid sick days a year. Similar proposals are under consideration in Philadelphia and Vermont.

In Massachusetts, supporters say these victories are boosting legislation that was first filed in 2005 but has foundered year after year in the face of strong opposition from businesses.

The sick-pay bill, now before the Joint Committee on Labor and Workforce Development, has about 90 House and Senate sponsors. That’s more than in any previous effort, partly because of successes in New York, San Francisco, Portland, Ore., and other places.

Jon Hurst, president of the Retailers Association of Massachusetts, said the success of sick-pay proposals is a growing concern for his members, particularly as they deal with potentially costly state and federal health insurance requirements.

“We’re still struggling with issues related to being the first state to pass mandated health insurance,” he said. “We need to be wary of broad-brush new mandates.”

Suzanne Kreiter/Globe Staff

Mark Cohen, the owner of OPR Systems, a recycling firm in Wilmington, opposes the proposed paid sick time mandate, saying costs are overwhelming small companies.

In Massachusetts, more than 900,000 private sector employees, or about one in three such workers, do not have paid sick leave, according to the Institute for Women’s Policy Research, a Washington think tank. These workers, primarily low-income, can lose pay — and sometimes their jobs — if they stay home because they or a family member are sick.

Elizabeth Grow of Amherst, a seasonal cafeteria worker, said that last year, when she needed to stay home with her sick daughter Estella, she was told she would lose her $10.50-an-hour job if she did not come work. Grow had to plead with her day-care provider, who only reluctantly agreed to take the ill 4-year-old that day.

“Most people don’t want to watch a child if they’re sick,” said Grow, adding that she went to work sick many times out of fear she would be fired. “There was no sick day policy, other than ‘Don’t miss any days.’ ”

Under the Massachusetts bill, companies with more than 10 employees must offer worker seven days of paid sick leave; companies with six to 10 employees would have to offer five paid sick days, and companies with fewer than six employees would be required to offer five days of unpaid sick leave.

The bill would supplement the federal Family and Medical Leave Act, which guarantees job protection for up to 12 weeks of unpaid leave a year for an employee to recover from a serious health condition or care for a family member. The federal law, however, covers only companies with 50 or more workers.

Representative Kay Khan, the Newton Democrat sponsoring the state bill, said it is ironic that paid sick leave legislation has failed so many times in Massachusetts, despite its reputation as liberal with a history of backing workers’ rights.

“There’s been a lot of opposition from the business community, but we’re moving ahead,” she said, adding with a note of caution: “The Legislature tends to be much more conservative than people realize.”

Businesses remain deeply opposed. Already saddled with some of the highest costs in the nation, they say that forcing businesses to take on additional expenses at a time when the economy is still weak could mean less hiring or perhaps lower wages. More broadly, they say, a sick-pay mandate would be another unwarranted intrusion by government into the private sector.

“Our members are unequivocal on this issue, and they’re saying, ‘Let me run my business,” because they need the freedom and latitude to build their own benefits packages,” said John Regan, executive vice president at Associated Industries of Massachusetts, the state’s largest business group. “The interference of government in what they do is completely unacceptable to them.”

Mark Cohen, owner of OPR Systems, a Wilmington shredding and recycling company, said he offers employees a week of paid vacation in their first four years with the company and two weeks to employees of more than four years. They are allowed to use that time if they are sick or need it to care for a sick relative, he said, adding that he aims to be flexible.

However, the 26-employee firm is struggling under the weight of state-mandated employee health care costs, workers compensation costs. and unemployment insurance payments. The recession also took a toll on businesses, as demand for recycled paper shrank globally.

Like other small-business owners, he said, he’s reluctant to hire when he knows his costs are on the rise. And he said he had concerns that employees who aren’t feeling great, but not very ill, would be more inclined to take time off.

The sick time proposal is “one of these things that makes people feel good but can be destructive,” he said. “It’s ridiculous, all the non-wage costs of running a business are going through the roof. And people wonder why there aren’t more jobs.”

State Senator Daniel A. Wolf, a Democrat representing the Cape and Islands and leading advocate of the bill, called the issue one of fundamental fairness, on par with child labor laws. The chief executive of the regional airline Cape Air, he said the company has offered paid sick leave since he founded it 25 years ago.

On average, he said, his employees use about half their allotted sick time of five days. More importantly, he said, employees don’t fear getting sick and losing a day’s pay — and perhaps their ability to pay the rent or put food on the table.

“This is not a significant increase in expense, and it has a huge impact on the quality of life that the employees have,” he said. “This will make an absolute difference in the lives of people.”